On the hotlist for removal is up to an inch of dust. A squad of specialist cleaners, working from scaffolding, are using brushes and sponges to polish up the delicate plasterwork without damaging it. Not only does dust make the ornate paintings and gilding look duller, if not removed it can eventually damage the surfaces.

At present, just one vestibule is being worked on, at an estimated cost of €130,000. The technicians need to pack everything away each night, as the house is still open for performances. The auditorium will be similarly spruced up over the summer break, which has been extended by two weeks to accommodate the work. Once completed, the operation won't need to be repeated for another 30 years.